Numerous solar-powered hats and other headwear have been designed with the intent of cooling the head of a wearer. A fan is typically placed on a brim of the hat or at an intersection of the hat's body and its brim so that the fan blows air onto the user's forehead or face, such as the headwear described in U.S. Pat. Nos. 6,032,291 ('291) and 4,893,356 ('356). There are several disadvantages of placing the fan unit in one of these locations.
First, a fan unit placed on the front brim or lower body portion of a hat is readily noticeable to others and is typically not very fashionable. Certainly, a fan unit placed at the front of the hat significantly detracts from the visual appeal of the associated piece of headwear. Accordingly in the prior art, solar-powered fan units have not been incorporated into fashion headwear and are generally relegated to novelty baseball caps and novelty safari pith helmet-style hats. Even if a wearer is unconcerned about the fashion issues presented by the fan unit, the solar cell panels are an additional detractor from the fashion desirability of a solar-powered hat. Typically, one or more solar cells are placed directly on the top of the hat or cap, such as is described in the '291 and '356 references. Given the unique look of solar cells, the true nature of the hat is revealed. In summary, the blatantly obvious fan combined with the equally obvious solar cells make the prior art solar-powered fan-cooled hat a novelty item that the great majority of hat wears would not consider wearing for fear of ridicule or chastisement.
Another problem of the prior art solar-powered fan caps is the manner in which the air from the fan is directed. In the cap of the '291 reference, the air is blown directly into a wearer's face. In the helmet of the '356 reference, the air is blown on the wearer's forehead and it washed therefrom over his/her face. While blowing air on or across a wearer's face may not be as problematic in the humid climate of the eastern half of the United States, it is particularly undesirable in the hot dry climates of the western United States. Specifically, the dry air acts to dry out the eyes of the wearer, which can make the wearer uncomfortable especially if he/she is wearing contact lenses. Further, by blowing a significant portion, if not all, of the air from the fan over or at a wearer's face, the air is not being utilized as efficiently as it could be to actively cool the wearer.
In the dry western climates, evaporative cooling is a particularly effective method of cooling whether used to cool individuals or entire buildings. By blowing hot dry air over or through a moist environment, the water evaporates thereby cooling the surrounding area through the transformation of heat energy into the latent heat of evaporation of the water. Generally, to most effectively to cool using evaporative cooling, dry air is passed over moist surfaces having relatively large surface areas. Typically, a person's face is neither particularly moist nor does it have a relatively large surface area. In contrast, when a person is hot, he/she typically sweats on the top of his/her head wherein a thin layer of water coats the person's strands of hair. Ideally, a fan of a solar-powered hat would blow air across the top of a wearer's head and/or through his/her hair.
The headwear of the '356 reference attempts to direct some of the fan's flow over the top of the head, although a significant portion is directed downwardly over the wearer's eyes and face. For additional potential cooling a moistened cooling pad is provided between the wearer's head and the bottom surface of the headwear's topside. Unfortunately as described below, several design flaws prevent the headwear taught in the '356 patent from being very effective.
In order for a fan to blow air effectively around the head, the fan must be capable of operating under static pressure conditions. Typically, once one starts blowing air into a confined space with limited air outlet locations, such as the area in a piece of headwear between the top of a wearer's head and the topside of the hat, the pressure in the confined space increases to a level greater than that of the ambient air. The airflow from the fan will then attempt to flow along a path of least resistance or away from the higher-pressure region. It is to be appreciated that the pressure differential need only be very small to cause the air to be diverted from flowing into a higher-pressure region. Considering the type of fan blades taught in the '356 reference and considering the placement of the fan relative to the inlet opening, the great majority of the air flow from the fan would be directed downwardly over the wearer's face or back around the outside of the fan blades (or impellers) and away from the wearer.
Additionally, to even gain a small amount flow of air over the head despite the static pressure difference, the motor must be relatively powerful when compared to the motors of headwear that exclusively blows a stream of air onto a wearer's face. Understandably, the more powerful the motor the more energy it utilizes. Accordingly, the headwear taught in the '356 reference requires the use of a battery power pack in addition to the solar panel, since the small solar panel taught in the reference cannot generate enough energy alone to operate the fan effectively. Further, because of the configuration of the headwear, there is not any effective place on the headwear to place additional solar cells. In general, concerning the construction type helmet taught in the '356 reference, the additional weight of a battery pack is not very significant, but when considering other lighter styles of hats more commonly worn by people recreationally, the additional weight of a battery pack could become burdensome and, perhaps more significantly, prevent a potential buyer from purchasing or using the headwear in the first place.